Spine membrane localization of AR and ER may be accomplished via palmitoylation of receptors (Figure 5), as judged from recent studies, including the finding that some populations of ERα and ERβ were plasma membrane-bound in cultured breast cancer cells MCF-7 (Pedram et al., 2006), and they were anchored via palmitoylation (Pedram et al., 2007). This evidence concerns the gene ESR1 and breast cancer.